I used kadee 148's. They are #5 couplers with whiskers as the springs so you don't need to use the inserts. They have worked in everything I have converted so far.
Here is a page that may help you with your conversions.
Check our Roger Hensley's Installing a Caboose Industries Ground Throw
Knuckle Couplers
Standard S-7 Clearances and the NMRA Gage (Plates)
Retrucking old r-t-r cars